Chapin Mesa milkvetch (Astragalus schmolliae) is an endemic, obligate pinon-juniper̴ woodland species that occupies approximately 2500 ha in southwest Colorado. In 2002 a crown fire burned 38% of the known distribution in Mesa Verde National Park. Initially, Chapin Mesa milkvetch (CMM) responded positively to the 2002 burn, increasing in density compared to unburned areas. Nine years post-fire (2011), the density in burned areas was nearly twice that of unburned transects. By 2013, the pattern had reversed, and by 2019, the juvenile and adult population in the burned area was reduced to half that of unburned (0.046 plants/m² vs. 0.089 plants/m²). Recruitment of CMM in burned areas in 2019 was near zero: 4 seedlings in 63 burned transects vs. 6079 seedlings in 105 unburned transects. The downward trend in CMM density in the burn is likely associated with intensified competition from the dense grass cover. Prior to the burn, the grass cover in the to-be-burned area was qualitatively similar to that in present day unburned areas, which is 15%, almost exclusively muttongrass (Poa fendleriana), a shallow-rooted bunch grass. In 2019, cheatgrass (Bromus tectorum) and western wheatgrass (Pascopyrum smithii), seeded in 2002, dominated the cover in the burn, averaging 45% cover, collectively. Management practices that assist the recovery of burned pinon-juniper̴ woodland (and therefore CMM), as well as preserving the remaining old-growth pinon-juniper̴ stands, are likely key to CMM long-term survival.

Protection and management of tallgrass prairie remnants are critical to the continued existence of this rare ecosystem. While effects of individual management events (especially fire and grazing) are understood relatively well, their combined, long-term effects are more difficult to predict. We examined how a large (283 ha) tallgrass prairie remnant in Texas responded to changes in management. Previously, the site had been hayed annually for ∼100 y. In 1987, management changed to prescribed fire in multiple seasons (average fire return interval of 3.5 y) and occasional grazing and haying. From 1996 through 2020, native species richness increased from 39 ± 3 to 47 ± 1 species on slopes and from 33 ± 5 to 44 ± 4 species on summits (mean ± standard error, 7.5 m² sample area). The number of specialist species (coefficient of conservatism ≥7) remained stable (slopes: 7 ± 0.4 to 10 ± 1; summits: 5 ± 1 to 8 ± 1). Forb cover increased dramatically (slopes: 44 ± 3% to 66 ± 5%; summits: 39 ± 7% to 65 ± 6%). While overall graminoid cover remained similar, cool-season graminoid cover increased (slopes: 4 ± 2% to 14 ± 2%; summits: 12 ± 9% to 18 ± 2%) and warm-season graminoid cover decreased (slopes: 49 ± 4% to 35 ± 3%; summits: 30 ± 6% to 26 ± 3%). Tree and shrub cover remained low (<3%). The site's large size and the repeated use of prescribed fire likely contributed to these outcomes. Because fire seasonality can favor either grasses or forbs, burning in multiple seasons can increase forb cover and diversity while still maintaining grass cover. Prairie remnants should be actively managed to avoid woody encroachment and to maintain diversity.

Structured demographic models can be valuable for assessing the status of at-risk plant species and for guiding efforts to protect and manage them, but they may be infrequently employed in assessments of species of conservation concern because they require data that are not often available to those charged with management. We constructed and analyzed matrix projection models for three populations of the threatened perennial plant species Euphorbia telephioides to reevaluate a prior assessment of stable status and to compare the conclusions of models based on different amounts of data. In contrast to the prior assessment, all of our models predicted population decline for all three populations. Projected growth rates were similar for models based on sparse sampling and those based on a larger more representative sample of individuals, but the models supported contrasting patterns of the sensitivity of population growth rate to individual demographic transitions. Models based on more complete data supported greater elasticity of growth rate to the demographic fates of small non-flowering plants, which had among the lowest elasticity values for models based on more sparse data. We conclude that even models based on limited data can be useful to species status assessments, but that more complete data may be necessary to identify targets for effective management.

Florida freshwater herbaceous marshes are inundated approximately 6–10 mo/y, have predominantly organic soils, and are maintained by fire, which restricts invasion by woody plants. Marshes are becoming dominated by willow (Salix caroliniana Michx.) throughout Florida. Corkscrew Swamp Sanctuary and Corkscrew Regional Ecosystem Watershed Management Area treated willows in marshes from 2008 to 2016 with helicopter herbicide treatments and mechanical shredding. Our objective was to determine if treatments were shifting vegetation closer to a desirable marsh community with burnable fuels. Untreated areas were compared with (1) all herbicide and all mechanical treatments, (2) imazapyr/glyphosate mixes and other herbicides, primarily glyphosate, and (3) three imazapyr/glyphosate combination mixing rates. Mechanical treatment areas had more desirable vegetation and grasses/sedges than herbicided areas. Herbicided areas had more cattails (Typha spp., a nuisance species), and less sawgrass (Cladium jamaicense Crantz) and grasses/sedges than untreated areas. Imazapyr/glyphosate and other herbicides (mostly glyphosate) had less cover of sawgrass and grasses/sedges than untreated areas, and other herbicides also had less desirable species cover than untreated areas. Sample size was small, but the strongest imazapyr/glyphosate mix had more cattails and the weakest mix had less willow than untreated areas, while both had less grasses/sedges than untreated areas. Although more expensive and difficult, mechanical treatments better retained and/or restored desirable marsh vegetation, which was our primary objective. Sawgrass and other grasses and sedges are excellent fuels for burning. Mechanical treatments also have significantly more cover of grasses and sedges than herbicide treatments, increasing the ability to burn hot and frequently.

Saltmarshes provide multiple ecosystem services, and some have been preserved as conservation areas. Studies indicate recreation-related vehicle use may be significantly degrading them. Saltmarshes have a low resistance and resilience to recreation-related trampling impacts; however, little is known about those associated with vehicle use under a specific management strategy. Drone imagery and GIS spatial analysis were used to determine the area and intensity of direct vehicle impacts within a New Zealand saltmarsh. The management plan allows vehicle entry as long as it does not substantially impact cultural, ecological, or mahinga kai (or food cultivation) values. It limits impacts of vehicles by meeting two goals: limiting the area of vehicle use to formal road corridors, and limiting particularly damaging behaviors of use, including entering the saltmarsh when conditions are wet, traveling more than 10 km per hour, and using traction equipment. Results demonstrated substantial impacts. Tire tracks were present in 66% of quadrats sampled, and were distributed across the length and breadth of the saltmarsh, covering 17% (approximately 207 ha) of the 1225 ha saltmarsh. About a third of these quadrats had track covers of 11–50%. Furthermore, particularly damaging vehicle use behaviors were widely evidenced, including deeply rutted mud, water channel initiation, and substantial loss and fragmentation of vegetation communities. Vehicle use is clearly eroding at least some of the cultural, ecological, and/or mahinga kai values for which the saltmarsh was conserved. While there are many indirect and direct measures for improving the current management strategy, none is likely to result in substantial reductions in vehicle impacts given the low resistance and resilience of saltmarshes to trampling. An alternative strategy that would lead to substantial reductions, and eventual recovery of the saltmarsh, would be to allow existing recreational activities, but deny vehicle entry.

Invasive species are recognized as one of the biggest threats to biodiversity and dealing with them is a daunting challenge for protected area managers. Prioritization based on multiple criteria has been traditionally recommended as essential for the effective management of invasive species. A systematic literature review was undertaken to assess to what extent the scientific literature provides guidelines for implementing priority systems as part of management strategies for invasive plants in protected areas. We detected only 27 studies published up to 2019 reporting some kind of prioritization. Most of them were limited to a list of species built from a combination of biological information extracted from literature and data on the extent and effects of their presence in the area. Our review also revealed that risk analysis has been commonly confounded with prioritization tools. Despite the generalized recognition of the impact of invasive plants on biodiversity, managers of protected areas lack readily applicable support from scientific literature to set up prioritization schemes.

Twenty years of monitoring data are assessed for trends in abundance of running buffalo clover (Trifolium stoloniferum), an endangered species found on the Fernow Experimental Forest in northeastern West Virginia, where the clover is found under various forest management intensities. Monitored locations were grouped for analysis into sites with common disturbance histories. Of the 13 sites, about half (46%, six sites) were found to have statistically significant trends between numbers of rooted crowns and time. Three out of eight sites with recent and sustained periodic disturbance showed a significant association between time and running buffalo clover counts and the trend is positive. Of the sites with no management or no recent harvest activity, three were found to have negative trends of running buffalo clover counts over time, although at only one site was this statistically significant. This analysis of monitoring data gives some support for previous findings that the number of running buffalo clover rooted crowns is tied to disturbance on the skid roads and increased light conditions created by periodic harvesting.

Reference sites with relatively unaltered plant communities are used regularly to establish targets for ecological restoration, yet few are free from anthropogenic disturbances. In this study, we sought to understand the capacity for native community indicators and other plant species to recover from abandoned woods roads and tilled soils within reference sites. We mapped disturbances in a 34 ha portion of the Wade Tract, an old-growth longleaf pine-wiregrass (Pinus palustris-Aristida stricta) woodland using GPS and LiDAR and counted stems of 25 native species (20 woody and 5 herbaceous) in plots within disturbances (n = 32; disturbed), 3 m adjacent to disturbances (n = 32; adjacent), and >5 m from any disturbance (n = 30; reference). Ten species were considered indicator species of intact longleaf pine woodlands. We also quantified soil conditions within the disturbed, adjacent, and reference sites. Disturbed sites had more compacted surface soils than adjacent or reference sites and, in a subset of the sites, soil bulk density and soil strength were greater in disturbed than in adjacent. Indicator species were less frequent in disturbed sites than in adjacent or reference sites (except for Quercus pumila). Three oaks (Q. incana, Q. margaretta, and Q. laevis) and 3 other woody species (Rhus copallinum, Sassafras albidum, and Morella cerifera) were significantly less common in the disturbed sites than in adjacent or reference sites. The near absence of some oaks and other woody species on disturbed sites warrants including these species as indicators of intact regional ground cover for longleaf pine woodlands. Legacies of small-scale soil disturbances in relatively undisturbed perennial-dominated ground cover flora reveals the potential for cumulative degradation over decades and underscores the need to avoid such disturbances in remnant longleaf pine woodlands.

The relative densities of co-flowering plant species can affect pollinator foraging behavior, i.e., bee choice of which plants to visit in a foraging path. Because animal-pollinated plants depend on sequential pollinator visits to conspecifics for successful reproduction, understanding the relationship between relative densities of co-flowering plants and bee visits within a foraging path is necessary to determine whether co-flowering species facilitate or compete for bee visitation. We examined the role of relative co-flowering plant species densities in determining bee visits to two focal plant species (Astragalus scaphoides and Penstemon albertinus) within foraging paths by following individual bees in natural multispecies co-flowering plant communities. We found that conspecific and heterospecific plant density influenced the proportion of visits to the focal plant species during foraging bouts, but effects of density differed among bee groups. Considering all bees, Lupinus spp. facilitated visits to A. scaphoides while Castilleja spp. competed with A. scaphoides for visits. When three bee groups, Bombus, Anthophora/Eucera, and “small bees,” were modeled separately, Bombus consistently visited A. scaphoides more than expected regardless of its density and P. albertinus less than expected at intermediate densities. Anthophora/Eucera exhibited a nonlinear response to A. scaphoides floral density but visited P. albertinus in direct proportion to its density. “Small bees” visited both plants in direct proportion to their densities. Our results highlight that bee groups should be treated separately in models of pollinator visitation behavior, and that the composition and density of the co-flowering plant community may impact reproductive success of focal plant species.